What are blue road reflectors for?

California has lots of little bumpy reflectors (hemispheres with a
radius of about an inch) built into its roads.  There are lines of
yellow nubbies down the center of really big streets  (possibly laid
on top of the traditional yellow paint lines) and lines of white
nubbies down the sides of freeways (also possibly accompanied by
paint). These nubbies are there so that when you start driving off the
road or into oncoming traffic, there is an audible and tactile
sensation that you should wake up from your drunken stupor and get
back into your lane.

So those reflectors make sense.  They are colored the same way their
corresponding lines are painted.  My question is about the blue ones. 
On the small residential street where I live, there are exactly two
blue nubby reflectors - but they're square ones.  Each is in the
middle of an intersection, although there are other intersections on
this street that do not have them. The two intersections share no
obvious feature - one is four-way, one is three-way; one has a stop
sign, one does not; one has a street light near it; one does not.  
I've seen the reflectors on an assortment of streets, not just in my
city.

 I want to know why these reflectors are blue and what they are
supposed to do.

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Request for Question Clarification by googlenut-ga on 25 Apr 2003 22:16 PDT

Hello Lexi,

Are the blue reflectors near fire hydrants?

Googlenut

Hello Lexi,

I’m going to go out on a limb and assume that the blue reflectors that
you are describing are near a fire hydrant or some other water supply.

According to the California Department of Transportation:
http://www.dot.ca.gov/hq/traffops/signtech/signdel/chp6/chap6.htm
“6-03.4 Location Markers - Fire Hydrants

Blue raised reflective pavement markers, although not an official
traffic control device, may be placed on a highway, street, or road,
to mark fire hydrant and/or water supply locations. They shall not be
used for any other purpose.”


In an interesting piece of trivia, these markers are also referred to
as “Botts’ Dots” in honor of their inventor Elbert D. Botts. You can
read more about this at the following web pages:

California Department of Transportation 
FACT SHEET, Botts' Dots
http://www.dot.ca.gov/hq/paffairs/about/botts.htm

Snopes.com, Botts' Dots
http://www.snopes.com/business/origins/bottsdot.htm


Snopes also mentions the blue markers:

“Botts' Dots come in two types, round and square, and in several
colors. Most are white, center markers are amber, wrong-way markers
are red, and fire hydrant markers are blue. On most multi-lane
freeways, Caltrans uses four white round non-reflective dots in a row,
interspersed every 48 feet with a reflective square, along the painted
stripes dividing lanes.”


Thanks for the interesting question. I also live in California and I
never knew the significance of the different colors.

Please let me know if you have any questions.

Googlenut


Search Strategy:

Searched California Department of Transportation website for:

blue reflectors street
reflective street blue


Google Search Terms:

california blue reflective markers hydrant
://www.google.com/search?q=california+blue+reflective+markers+hydrant&btnG=Google+Search&hl=en&lr=&ie=ISO-8859-1&safe=off

Cool.  I had no idea there were so many fire hydrants in my neighborhood.

Thank you for the 5 stars and the tip!

Googlenut